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<head><meta charset="utf-8"><title>I-prioritize #78532 VecDeque from Vec fails with ZST · t-compiler/wg-prioritization/alerts · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/index.html">t-compiler/wg-prioritization/alerts</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2378532.20VecDeque.20from.20Vec.20fails.20with.20ZST.html">I-prioritize #78532 VecDeque from Vec fails with ZST</a></h3>

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<a name="215026458"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2378532%20VecDeque%20from%20Vec%20fails%20with%20ZST/near/215026458" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> triagebot <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2378532.20VecDeque.20from.20Vec.20fails.20with.20ZST.html#215026458">(Oct 29 2020 at 20:55)</a>:</h4>
<p><span class="user-group-mention" data-user-group-id="3111">@WG-prioritization/alerts</span> issue <a href="https://github.com/rust-lang/rust/issues/78532">#78532</a> has been requested for prioritization.</p>
<h1><a href="https://forge.rust-lang.org/compiler/prioritization/procedure.html#assign-priority-to-unprioritized-issues-with-i-prioritize-label">Procedure</a></h1>
<ul>
<li>Priority?</li>
<li>Regression?</li>
<li>Notify people/groups?</li>
<li>Needs <code>I-nominated</code>?</li>
</ul>



<a name="215026597"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2378532%20VecDeque%20from%20Vec%20fails%20with%20ZST/near/215026597" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Noah Lev <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2378532.20VecDeque.20from.20Vec.20fails.20with.20ZST.html#215026597">(Oct 29 2020 at 20:56)</a>:</h4>
<p>P-high?</p>



<a name="215026741"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2378532%20VecDeque%20from%20Vec%20fails%20with%20ZST/near/215026741" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2378532.20VecDeque.20from.20Vec.20fails.20with.20ZST.html#215026741">(Oct 29 2020 at 20:57)</a>:</h4>
<p>yeah, seems about right <span aria-label="thumbs up" class="emoji emoji-1f44d" role="img" title="thumbs up">:thumbs_up:</span> I fear that <code>VecDeque</code> probably has more issues with ZSTs than just that though</p>



<a name="215026841"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2378532%20VecDeque%20from%20Vec%20fails%20with%20ZST/near/215026841" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2378532.20VecDeque.20from.20Vec.20fails.20with.20ZST.html#215026841">(Oct 29 2020 at 20:58)</a>:</h4>
<p>there really shouldn't be a reason to use a queue of objects carrying no information, so we have close to no usage or test coverage here</p>



<a name="215026856"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2378532%20VecDeque%20from%20Vec%20fails%20with%20ZST/near/215026856" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Noah Lev <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2378532.20VecDeque.20from.20Vec.20fails.20with.20ZST.html#215026856">(Oct 29 2020 at 20:58)</a>:</h4>
<p>I'll wait for a bit to see if anyone disagrees with the priority</p>



<a name="215028656"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2378532%20VecDeque%20from%20Vec%20fails%20with%20ZST/near/215028656" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2378532.20VecDeque.20from.20Vec.20fails.20with.20ZST.html#215028656">(Oct 29 2020 at 21:11)</a>:</h4>
<p>Seems good to me, though maybe I'd have expected <code>P-medium</code> here</p>



<a name="215028761"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2378532%20VecDeque%20from%20Vec%20fails%20with%20ZST/near/215028761" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Joshua Nelson <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2378532.20VecDeque.20from.20Vec.20fails.20with.20ZST.html#215028761">(Oct 29 2020 at 21:12)</a>:</h4>
<p>P-medium sounds good to me, you'd have to do this intentionally and it's a panic, not a crash or unsoundness</p>



<a name="215028839"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2378532%20VecDeque%20from%20Vec%20fails%20with%20ZST/near/215028839" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Léo Lanteri Thauvin <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2378532.20VecDeque.20from.20Vec.20fails.20with.20ZST.html#215028839">(Oct 29 2020 at 21:13)</a>:</h4>
<p>Plus IIUC it's been there unnoticed for a long time?</p>



<a name="215030671"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2378532%20VecDeque%20from%20Vec%20fails%20with%20ZST/near/215030671" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Noah Lev <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2378532.20VecDeque.20from.20Vec.20fails.20with.20ZST.html#215030671">(Oct 29 2020 at 21:27)</a>:</h4>
<p>I still think P-high is better just to be on the safe side. It's possible there's some valid use case for a queue of ZSTs -- maybe something like Diesel's type magic</p>



<a name="215030707"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2378532%20VecDeque%20from%20Vec%20fails%20with%20ZST/near/215030707" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Noah Lev <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2378532.20VecDeque.20from.20Vec.20fails.20with.20ZST.html#215030707">(Oct 29 2020 at 21:27)</a>:</h4>
<p>But I'm okay with P-medium as well</p>



<a name="215030835"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2378532%20VecDeque%20from%20Vec%20fails%20with%20ZST/near/215030835" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lcnr <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2378532.20VecDeque.20from.20Vec.20fails.20with.20ZST.html#215030835">(Oct 29 2020 at 21:28)</a>:</h4>
<p>i am not completely certain that we can't cause ub here tbh</p>



<a name="215030850"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2378532%20VecDeque%20from%20Vec%20fails%20with%20ZST/near/215030850" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Noah Lev <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2378532.20VecDeque.20from.20Vec.20fails.20with.20ZST.html#215030850">(Oct 29 2020 at 21:29)</a>:</h4>
<p>Ok, going with P-high then</p>



<a name="215030870"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize%20%2378532%20VecDeque%20from%20Vec%20fails%20with%20ZST/near/215030870" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> triagebot <a href="https://rust-lang.github.io/zulip_archive/stream/245100-t-compiler/wg-prioritization/alerts/topic/I-prioritize.20.2378532.20VecDeque.20from.20Vec.20fails.20with.20ZST.html#215030870">(Oct 29 2020 at 21:29)</a>:</h4>
<p>Issue <a href="https://github.com/rust-lang/rust/issues/78532">#78532</a>'s prioritization request has been removed.</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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